Waterways are a major mode of transport for the world's petrochemical supply. Although there are tremendous benefits and necessities for shipping over water, there are also risks as witness by the over 30 significant oil spills (i.e., >7000 tons of crude released per incident) since 2000. (Huijer, K. Trends in Oil Spills from Tanker Ships. 2012 [cited 2012 Sep. 25, 2012]; Available from: http://www.itopf.com/_assets/documents/amop05.pdf).
Confounding the issue, underwater exploration and offshore drilling increase the risks of petrochemicals entering our waterways as was observed in 2010 when nearly 5 billion barrels of crude oil were released in the Gulf of Mexico. (Hoch, M. New Estimate Puts Gulf Oil Leak at 205 Million Gallons, [2012 on Sep. 25, 2012]; Available from http://www.pbs.org/newshour/rundown/2010/08/new-estimate-puts-oil-leak-at-49-million-barrels.html). Each incident has a devastating effect on Earth's delicate ecosystems. The presence of both crude oil and the chemical dispersants used to disperse the oil can disrupt sensitive food webs and create situations of bioaccumulation where toxins progressively climb up trophic levels of a food chain.
Current materials used to reclaim oil are subdivided into three primary categories including: dispersants, sorbents and solidifiers. (Jadhav, R. S., et al., Sugar-Derived Phase-Selective Molecular Gelators as Model Solidifiers for Oil Spills. Angewandte Chemie, 2010. 49: p. 7695-7698). Dispersants are most commonly used where the material emulsifies the oil spill into small finely divided droplets which are dispersed into the environment. (Lessard, R. R. and G. DeMarco, The Significance of Oil Spill Dispersants. Spill Science & Technology Bulletin, 2000. 6: p. 59-68; and Chapman, H., et al., The use of chemical dispersants to combat oil spills at sea: A review of practice and research needs in Europe. Marine Pollution Bulletin, 2007. 54: p. 827-838). Sorbents are typically powders that selectively adsorb the oil via capillary forces of the super-hydrophobic matrix. (Yuan. J., et al., Superwetting nanowire membranes for selective absorption. Nature Nanotechnology, 2008. 3: p. 332-336; Thanikaivelan, P., et al., Collagen based magnetic nanocomposites for oil removal applications. Scientific Reports, 2012. 2; p. 230-237; Karakutuk, I. and O. Okay, Macroporous rubber gels as reusable sorbents for the removal of oil from surface waters. Reactive & Functional Polymers, 2010. 70: p. 585-595). Solidifiers gel the material on the surface of the water using either polymeric or monomeric gelators. (Jadhav, R. S., et al., Sugar-Derived Phase-Selective Molecular Gelators as Model Solidifiers for Oil Spills. Angewandte Chemie, 2010. 49: p. 7695-7698; Basak, S., J. Nanda, and A. Banerjee, A new aromatic amino acid based organogel for oil spill recovery. Journal of Materials Chemistry, 2012. 22: p. 11568-11664; Mallia, V. A. and R. G. Weiss, Low molecular weight gelators for crude oil, petrolium product or chemical spill containment, 2012). Ideally, any material used to treat spilled oil in our waterways must selectively remove the oil phase from water, be environmentally benign, allow oil to be reclaimed and the material should be recyclable or reusable. (Jadhav, R. S., et al., Sugar-Derived Phase-Selective Molecular Gelators as Model Solidifiers for Oil Spills. Angewandte Chemie, 2010. 49: p. 7695-7698). Recently, there has been a surge in research interest in utilizing amphiphilic solidifiers based on numerous molecular gelators including: sugar alcohols, (Jadhav, R. S., et al., Sugar-Derived Phase-Selective Molecular Gelators as Model Solidifiers for Oil Spills. Angewandte Chemie, 2010. 49: p. 7695-7698) amino acid amphiphiles, (Bhattacharya, S. and Y. Krishnan-Ghosh, First report of phase selective gelation of oil from oil/water mixtures. Possible implication toward containing oil spills. Chemical Communication, 2001: p. 185-186) aromatic amino acids, (Basak, S., J. Nanda, and A. Banerjee, A new aromatic amino acid based organogel for oil spill recovery. Journal of Materials Chemistry, 2012. 22: p. 11568-11664) and modified 12-hydroxy-N-alkyloctadecanamide. (Mallia, V. A. and R. G. Weiss, Low molecular weight gelators for crude oil, petrolium product or chemical spill containment, 2012.) Although this is a promising technology there are practical drawbacks, which involve the kinetics and thermodynamics of gelation on such extensive scales. For example, when applying the gelator over large areas, dilution of the gelator may prevent solidification. Therefore, a need exists for alternative materials and methods for remediating oil and other chemical spills.